胶凝砂砾石料剪胀特性试验

为探究弹性和塑性对胶凝砂砾石料(CSG)应力应变特性的影响，建立了适用于CSG的剪胀方程，参考粗粒土或堆石料剪胀特性的研究方式开展了一系列不同掺量和围压下的三轴压缩试验、三轴等向加卸载试验和三轴轴向加卸载试验，对CSG的剪胀特性进行了系统研究。试验结果表明：CSG加载过程中弹性和塑性应变都不可忽略，CSG在低围压下具有剪胀性，随着围压的增大逐渐向剪缩性过渡；由试验数据得到CSG的弹性体积应变和弹性剪应变，对比分析了考虑和不考虑弹性应变的CSG剪胀特性曲线，发现弹性应变对CSG剪胀特性影响较大，仅在高掺量、高围压、大应力条件下可以忽略弹性应变的影响；二次函数可以很好地描述CSG的剪胀特性。

Experimental study on shear dilatancy characteristics of CSG

In order to investigate the effects of elasticity and plasticity on the stress-strain characteristics of cement sand and gravel (CSG) and to establish the dilatancy equation, a series of triaxial compression tests, isotropic loading and unloading tests, and triaxial loading and unloading tests of CSG materials with different cement contents under different confining pressures were carried out to systematically study the dilatancy characteristics, by means of the research method for the dilatancy characteristics of coarse-grained soil or rockfill. The results show that, both elastic and plastic strains cannot be ignored during the loading of CSG, and the CSG shows the dilatancy under the low confining pressure, while the dilatancy transits to the shrinkage with the increase of confining pressure. The elastomer strain and elastic shear strain of CSG were obtained by test data and dilatancy characteristic curves of CSG materials with and without considering elastic strain were also compared. The study reveals that the elastic strain of CSG has a greater influence on the dilatancy, and only with the high cement content and under the high confining pressure, the influence of elastic strain can be ignored. Finally, the quadratic function can well describe the dilatancy characteristics of CSG.